Noting that “the Examiner is attempting to impose a requirement that a dependent claim must recite ‘structure’ in addition to any functional limitations,” Appellants argue that “patent claims may define an invention functionally, i.e., by what it does.” Appeal Br. 7. Appellants are correct. We are unaware of any requirement that a dependent claim further define the structure of the claim from which it depends. Rather, “[t]here is nothing inherently wrong with defining some part of an invention in functional terms.” MPEP § 2173.05(g). Functional language does not, in and of itself, render a claim improper. In re Swinehart, 439 F. 2d 210, 212 (CCPA 1971).